The purpose of the Etiology of Childhood Obesity (ECHO) study is to examine the etiology of childhood obesity using a socio-ecological approach considering possible risk and protective factors at individual, family, school, and neighborhood levels. Obesity in adolescence is related to increased cardiovascular risk in adulthood. Approximately 60% of overweight youth have one CVD risk factor and another 25% have more than one risk factor. We will recruit 400 youth between the ages of 10 and 13 and one of their biological parents, conduct measurements and follow them for two years. We will target our recruitment to include youth who are at risk for, or who are overweight (at or above the 85th percentile of BMI using the CDC growth curves) and those who are in the recommended weight range and will over sample by zip code to ensure economic and racial/ethnic diversity. Individual measures on youth will include fasting blood glucose, blood lipids, anthropometry, blood pressure, and psychosocial, preference and socioeconomic status, family history related to weight including child's birth weight, early feeding (practices such as breast-feeding, family history of obesity and obesity-related chronic disease), family meal and activity patterns, and the home food and activity environments. We will measure the height, weight, waist and hip circumference of both of the youth's biological parents. For each youth in the study, we will collect data on their school environment including opportunities for physical activity, food options available in the school cafeteria and throughout the school, and school food and activity policies. Neighborhood level measures will be obtained using Geographical Information System (GIS) methodologies to assess obesogenic environmental factors such as the presence of walking and bike paths, convenience stores and fast food restaurants proximal to each youth's home and school. This research is timely and important because it will: 1) identify obesogenic factors at multiple levels of the environment guided by a social-ecological theoretical framework;2) include a diverse sample of youth from a large, urban community;3)'focus on modifiable risk and protective factors and use state of the science methods to measure them;4) be directed by an experienced and multidisciplinary team of investigators;and 5) provide essential information for multi-level interventions to prevent childhood obesity.